Lessons learnt from an aggressive tumour masquerading as a neuropathic heel ulcer: a case report

Cutaneous malignant melanoma (cMM) can develop at any site, but one-third of cases primarily affect the lower extremities, with ankle and foot lesions representing 3-15% of all cases. However, cMM may become a clinical conundrum when it presents as chronic ulceration that is clinically indiscernible from other lower extremity ulcers in patients with diabetes. We present the case of a 71-year-old female patient with a longstanding history of diabetes, hypertension, obesity, chronic kidney disease and heart failure who presented to our hospital with a fungating heel ulcer. The lesion was initially managed in another hospital as a neuropathic diabetic foot ulcer (DFU), treated by multiple local wound debridement. However, the ulcer progressed into a fungating heel lesion that interfered with the patient's mobility and quality of life. Consequently, the patient was referred to our specialist diabetic foot service for further management. Excisional biopsy of the lesion disclosed a cMM. Positron emission tomography/computed-tomography scanning revealed hypermetabolic ipsilateral inguinal lymphadenopathy, and a right cerebral metastasis for which palliative chemotherapy was initiated. Immunotherapy was considered, but the patient died before it was started. Atypical foot ulcers in patients with diabetes warrant a careful diagnostic approach, especially for recalcitrant cutaneous lesions not responding to standard therapies. Conscientious management, without undue delay in obtaining a histopathological diagnosis, might lead to early diagnosis of melanoma and potentially more favourable outcomes. This case highlights the importance of consideration of atypical foot lesions, in general practice in addition to referral centres, to try to identify alarming features and act accordingly.